Rough idle after plug change

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Aug 1, 2008 | 09:14 PM

Mr. Obvious

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Rough idle after plug change

I noticed after changing my plugs and boots the Ex V10 seemed to have a little rougher idle. Before it was perfectly smooth but after I could feel a little roughness which goes away as soon as the rpm's go up. Definitely not a full miss on a cylinder.

I have seen a few other people report this on the 5.4 engine.

Any plug changers notice this on their V10? On the 5.4 they suggest disconnect the battery for a few minutes but that may or may not fix it. Definitely didn't disconnect any vacuum hoses during the change.

Any thoughts?

Aug 1, 2008 | 09:22 PM

sidestep

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what year is the ford? What type of plugs did you replace it with.

Aug 1, 2008 | 09:30 PM

Antelope V-10

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I noticed this on my first start up after changing plugs. I attributed it to the truck sitting for almost a week without running. It has smoothed out nice though. Runs great. Did yours smooth out?

Aug 1, 2008 | 11:46 PM

Monster-4

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From: Millersburg, OH

I had the same thing after changing my plugs. I hooked up my ODB scanner and it showed two bad COPs. Might be worth hooking one up and checking. If you don't have one take a trip down to Advanced Auto or Autozone and borrowing their scanner.

Aug 2, 2008 | 11:29 AM

krewat

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From: Long Island USA

What brand plugs did you use?

Aug 2, 2008 | 01:43 PM

Mr. Obvious

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I used the recommended motorcraft plugs with the longer threads as compared to the old plugs.
The boots were from NAPA.

Would my scangauge pick up on bad cop's? I haven't had a chance to read the manual for it yet.

I have not driven it for the past week so don't know if it improved while resting in the shaded garage.